Enable plan tool by default (#5384)

## Summary
- make the plan tool available by default by removing the feature flag
and always registering the handler
- drop plan-tool CLI and API toggles across the exec, TUI, MCP server,
and app server code paths
- update tests and configs to reflect the always-on plan tool and guard
workspace restriction tests against env leakage

## Testing
Manually tested the extension. 
------
https://chatgpt.com/codex/tasks/task_i_68f67a3ff2d083209562a773f814c1f9

codex-rs/app-server-protocol/src/protocol.rs

@@ -247,10 +247,6 @@ pub struct NewConversationParams {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub base_instructions: Option<String>,
 
-    /// Whether to include the plan tool in the conversation.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub include_plan_tool: Option<bool>,
-
     /// Whether to include the apply patch tool in the conversation.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub include_apply_patch_tool: Option<bool>,
@@ -886,7 +882,6 @@ mod tests {
                 sandbox: None,
                 config: None,
                 base_instructions: None,
-                include_plan_tool: None,
                 include_apply_patch_tool: None,
             },
         };

codex-rs/app-server/src/codex_message_processor.rs

@@ -1421,7 +1421,6 @@ async fn derive_config_from_params(
         sandbox: sandbox_mode,
         config: cli_overrides,
         base_instructions,
-        include_plan_tool,
         include_apply_patch_tool,
     } = params;
     let overrides = ConfigOverrides {
@@ -1434,7 +1433,6 @@ async fn derive_config_from_params(
         model_provider: None,
         codex_linux_sandbox_exe,
         base_instructions,
-        include_plan_tool,
         include_apply_patch_tool,
         include_view_image_tool: None,
         show_raw_agent_reasoning: None,

codex-rs/core/src/codex.rs

@@ -1386,9 +1386,8 @@ async fn spawn_review_thread(
     let model = config.review_model.clone();
     let review_model_family = find_family_for_model(&model)
         .unwrap_or_else(|| parent_turn_context.client.get_model_family());
-    // For reviews, disable plan, web_search, view_image regardless of global settings.
+    // For reviews, disable web_search and view_image regardless of global settings.
     let mut review_features = config.features.clone();
-    review_features.disable(crate::features::Feature::PlanTool);
     review_features.disable(crate::features::Feature::WebSearchRequest);
     review_features.disable(crate::features::Feature::ViewImageTool);
     review_features.disable(crate::features::Feature::StreamableShell);

codex-rs/core/src/config.rs

@@ -216,9 +216,6 @@ pub struct Config {
     /// When set, restricts the login mechanism users may use.
     pub forced_login_method: Option<ForcedLoginMethod>,
 
-    /// Include an experimental plan tool that the model can use to update its current plan and status of each step.
-    pub include_plan_tool: bool,
-
     /// Include the `apply_patch` tool for models that benefit from invoking
     /// file edits as a structured tool call. When unset, this falls back to the
     /// model family's default preference.
@@ -1117,7 +1114,6 @@ pub struct ConfigOverrides {
     pub config_profile: Option<String>,
     pub codex_linux_sandbox_exe: Option<PathBuf>,
     pub base_instructions: Option<String>,
-    pub include_plan_tool: Option<bool>,
     pub include_apply_patch_tool: Option<bool>,
     pub include_view_image_tool: Option<bool>,
     pub show_raw_agent_reasoning: Option<bool>,
@@ -1147,7 +1143,6 @@ impl Config {
             config_profile: config_profile_key,
             codex_linux_sandbox_exe,
             base_instructions,
-            include_plan_tool: include_plan_tool_override,
             include_apply_patch_tool: include_apply_patch_tool_override,
             include_view_image_tool: include_view_image_tool_override,
             show_raw_agent_reasoning,
@@ -1174,7 +1169,6 @@ impl Config {
         };
 
         let feature_overrides = FeatureOverrides {
-            include_plan_tool: include_plan_tool_override,
             include_apply_patch_tool: include_apply_patch_tool_override,
             include_view_image_tool: include_view_image_tool_override,
             web_search_request: override_tools_web_search_request,
@@ -1269,7 +1263,6 @@ impl Config {
 
         let history = cfg.history.unwrap_or_default();
 
-        let include_plan_tool_flag = features.enabled(Feature::PlanTool);
         let include_apply_patch_tool_flag = features.enabled(Feature::ApplyPatchFreeform);
         let include_view_image_tool_flag = features.enabled(Feature::ViewImageTool);
         let tools_web_search_request = features.enabled(Feature::WebSearchRequest);
@@ -1399,7 +1392,6 @@ impl Config {
                 .unwrap_or("https://chatgpt.com/backend-api/".to_string()),
             forced_chatgpt_workspace_id,
             forced_login_method,
-            include_plan_tool: include_plan_tool_flag,
             include_apply_patch_tool: include_apply_patch_tool_flag,
             tools_web_search_request,
             use_experimental_streamable_shell_tool,
@@ -1765,7 +1757,6 @@ approve_all = true
         profiles.insert(
             "work".to_string(),
             ConfigProfile {
-                include_plan_tool: Some(true),
                 include_view_image_tool: Some(false),
                 ..Default::default()
             },
@@ -1782,9 +1773,7 @@ approve_all = true
             codex_home.path().to_path_buf(),
         )?;
 
-        assert!(config.features.enabled(Feature::PlanTool));
         assert!(!config.features.enabled(Feature::ViewImageTool));
-        assert!(config.include_plan_tool);
         assert!(!config.include_view_image_tool);
 
         Ok(())
@@ -1794,7 +1783,6 @@ approve_all = true
     fn feature_table_overrides_legacy_flags() -> std::io::Result<()> {
         let codex_home = TempDir::new()?;
         let mut entries = BTreeMap::new();
-        entries.insert("plan_tool".to_string(), false);
         entries.insert("apply_patch_freeform".to_string(), false);
         let cfg = ConfigToml {
             features: Some(crate::features::FeaturesToml { entries }),
@@ -1807,9 +1795,7 @@ approve_all = true
             codex_home.path().to_path_buf(),
         )?;
 
-        assert!(!config.features.enabled(Feature::PlanTool));
         assert!(!config.features.enabled(Feature::ApplyPatchFreeform));
-        assert!(!config.include_plan_tool);
         assert!(!config.include_apply_patch_tool);
 
         Ok(())
@@ -2908,7 +2894,6 @@ model_verbosity = "high"
                 base_instructions: None,
                 forced_chatgpt_workspace_id: None,
                 forced_login_method: None,
-                include_plan_tool: false,
                 include_apply_patch_tool: false,
                 tools_web_search_request: false,
                 use_experimental_streamable_shell_tool: false,
@@ -2977,7 +2962,6 @@ model_verbosity = "high"
             base_instructions: None,
             forced_chatgpt_workspace_id: None,
             forced_login_method: None,
-            include_plan_tool: false,
             include_apply_patch_tool: false,
             tools_web_search_request: false,
             use_experimental_streamable_shell_tool: false,
@@ -3061,7 +3045,6 @@ model_verbosity = "high"
             base_instructions: None,
             forced_chatgpt_workspace_id: None,
             forced_login_method: None,
-            include_plan_tool: false,
             include_apply_patch_tool: false,
             tools_web_search_request: false,
             use_experimental_streamable_shell_tool: false,
@@ -3131,7 +3114,6 @@ model_verbosity = "high"
             base_instructions: None,
             forced_chatgpt_workspace_id: None,
             forced_login_method: None,
-            include_plan_tool: false,
             include_apply_patch_tool: false,
             tools_web_search_request: false,
             use_experimental_streamable_shell_tool: false,

codex-rs/core/src/config_profile.rs

@@ -20,7 +20,6 @@ pub struct ConfigProfile {
     pub model_verbosity: Option<Verbosity>,
     pub chatgpt_base_url: Option<String>,
     pub experimental_instructions_file: Option<PathBuf>,
-    pub include_plan_tool: Option<bool>,
     pub include_apply_patch_tool: Option<bool>,
     pub include_view_image_tool: Option<bool>,
     pub experimental_use_unified_exec_tool: Option<bool>,

codex-rs/core/src/features.rs

@@ -33,8 +33,6 @@ pub enum Feature {
     StreamableShell,
     /// Use the official Rust MCP client (rmcp).
     RmcpClient,
-    /// Include the plan tool.
-    PlanTool,
     /// Include the freeform apply_patch tool.
     ApplyPatchFreeform,
     /// Include the view_image tool.
@@ -74,7 +72,6 @@ pub struct Features {
 
 #[derive(Debug, Clone, Default)]
 pub struct FeatureOverrides {
-    pub include_plan_tool: Option<bool>,
     pub include_apply_patch_tool: Option<bool>,
     pub include_view_image_tool: Option<bool>,
     pub web_search_request: Option<bool>,
@@ -83,7 +80,6 @@ pub struct FeatureOverrides {
 impl FeatureOverrides {
     fn apply(self, features: &mut Features) {
         LegacyFeatureToggles {
-            include_plan_tool: self.include_plan_tool,
             include_apply_patch_tool: self.include_apply_patch_tool,
             include_view_image_tool: self.include_view_image_tool,
             tools_web_search: self.web_search_request,
@@ -158,7 +154,6 @@ impl Features {
         }
 
         let profile_legacy = LegacyFeatureToggles {
-            include_plan_tool: config_profile.include_plan_tool,
             include_apply_patch_tool: config_profile.include_apply_patch_tool,
             include_view_image_tool: config_profile.include_view_image_tool,
             experimental_use_freeform_apply_patch: config_profile
@@ -225,12 +220,6 @@ pub const FEATURES: &[FeatureSpec] = &[
         stage: Stage::Experimental,
         default_enabled: false,
     },
-    FeatureSpec {
-        id: Feature::PlanTool,
-        key: "plan_tool",
-        stage: Stage::Stable,
-        default_enabled: false,
-    },
     FeatureSpec {
         id: Feature::ApplyPatchFreeform,
         key: "apply_patch_freeform",

codex-rs/core/src/features/legacy.rs

@@ -29,10 +29,6 @@ const ALIASES: &[Alias] = &[
         legacy_key: "include_apply_patch_tool",
         feature: Feature::ApplyPatchFreeform,
     },
-    Alias {
-        legacy_key: "include_plan_tool",
-        feature: Feature::PlanTool,
-    },
     Alias {
         legacy_key: "include_view_image_tool",
         feature: Feature::ViewImageTool,
@@ -55,7 +51,6 @@ pub(crate) fn feature_for_key(key: &str) -> Option<Feature> {
 
 #[derive(Debug, Default)]
 pub struct LegacyFeatureToggles {
-    pub include_plan_tool: Option<bool>,
     pub include_apply_patch_tool: Option<bool>,
     pub include_view_image_tool: Option<bool>,
     pub experimental_use_freeform_apply_patch: Option<bool>,
@@ -68,12 +63,6 @@ pub struct LegacyFeatureToggles {
 
 impl LegacyFeatureToggles {
     pub fn apply(self, features: &mut Features) {
-        set_if_some(
-            features,
-            Feature::PlanTool,
-            self.include_plan_tool,
-            "include_plan_tool",
-        );
         set_if_some(
             features,
             Feature::ApplyPatchFreeform,

codex-rs/core/src/tools/spec.rs

@@ -25,7 +25,6 @@ pub enum ConfigShellToolType {
 #[derive(Debug, Clone)]
 pub(crate) struct ToolsConfig {
     pub shell_type: ConfigShellToolType,
-    pub plan_tool: bool,
     pub apply_patch_tool_type: Option<ApplyPatchToolType>,
     pub web_search_request: bool,
     pub include_view_image_tool: bool,
@@ -46,7 +45,6 @@ impl ToolsConfig {
         } = params;
         let use_streamable_shell_tool = features.enabled(Feature::StreamableShell);
         let experimental_unified_exec_tool = features.enabled(Feature::UnifiedExec);
-        let include_plan_tool = features.enabled(Feature::PlanTool);
         let include_apply_patch_tool = features.enabled(Feature::ApplyPatchFreeform);
         let include_web_search_request = features.enabled(Feature::WebSearchRequest);
         let include_view_image_tool = features.enabled(Feature::ViewImageTool);
@@ -73,7 +71,6 @@ impl ToolsConfig {
 
         Self {
             shell_type,
-            plan_tool: include_plan_tool,
             apply_patch_tool_type,
             web_search_request: include_web_search_request,
             include_view_image_tool,
@@ -870,10 +867,8 @@ pub(crate) fn build_specs(
     builder.register_handler("list_mcp_resource_templates", mcp_resource_handler.clone());
     builder.register_handler("read_mcp_resource", mcp_resource_handler);
 
-    if config.plan_tool {
+    builder.push_spec(PLAN_TOOL.clone());
-        builder.push_spec(PLAN_TOOL.clone());
+    builder.register_handler("update_plan", plan_handler);
-        builder.register_handler("update_plan", plan_handler);
-    }
 
     if let Some(apply_patch_tool_type) = &config.apply_patch_tool_type {
         match apply_patch_tool_type {
@@ -1006,7 +1001,6 @@ mod tests {
         let model_family = find_family_for_model("codex-mini-latest")
             .expect("codex-mini-latest should be a valid model family");
         let mut features = Features::with_defaults();
-        features.enable(Feature::PlanTool);
         features.enable(Feature::WebSearchRequest);
         features.enable(Feature::UnifiedExec);
         let config = ToolsConfig::new(&ToolsConfigParams {
@@ -1033,7 +1027,6 @@ mod tests {
     fn test_build_specs_default_shell() {
         let model_family = find_family_for_model("o3").expect("o3 should be a valid model family");
         let mut features = Features::with_defaults();
-        features.enable(Feature::PlanTool);
         features.enable(Feature::WebSearchRequest);
         features.enable(Feature::UnifiedExec);
         let config = ToolsConfig::new(&ToolsConfigParams {
@@ -1162,6 +1155,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "web_search",
                 "view_image",
                 "test_server/do_something_cool",
@@ -1281,6 +1275,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "view_image",
                 "test_server/cool",
                 "test_server/do",
@@ -1332,6 +1327,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "apply_patch",
                 "web_search",
                 "view_image",
@@ -1340,7 +1336,7 @@ mod tests {
         );
 
         assert_eq!(
-            tools[7].spec,
+            tools[8].spec,
             ToolSpec::Function(ResponsesApiTool {
                 name: "dash/search".to_string(),
                 parameters: JsonSchema::Object {
@@ -1400,6 +1396,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "apply_patch",
                 "web_search",
                 "view_image",
@@ -1407,7 +1404,7 @@ mod tests {
             ],
         );
         assert_eq!(
-            tools[7].spec,
+            tools[8].spec,
             ToolSpec::Function(ResponsesApiTool {
                 name: "dash/paginate".to_string(),
                 parameters: JsonSchema::Object {
@@ -1466,6 +1463,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "apply_patch",
                 "web_search",
                 "view_image",
@@ -1473,7 +1471,7 @@ mod tests {
             ],
         );
         assert_eq!(
-            tools[7].spec,
+            tools[8].spec,
             ToolSpec::Function(ResponsesApiTool {
                 name: "dash/tags".to_string(),
                 parameters: JsonSchema::Object {
@@ -1534,6 +1532,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "apply_patch",
                 "web_search",
                 "view_image",
@@ -1541,7 +1540,7 @@ mod tests {
             ],
         );
         assert_eq!(
-            tools[7].spec,
+            tools[8].spec,
             ToolSpec::Function(ResponsesApiTool {
                 name: "dash/value".to_string(),
                 parameters: JsonSchema::Object {
@@ -1639,6 +1638,7 @@ mod tests {
                 "list_mcp_resources",
                 "list_mcp_resource_templates",
                 "read_mcp_resource",
+                "update_plan",
                 "apply_patch",
                 "web_search",
                 "view_image",
@@ -1647,7 +1647,7 @@ mod tests {
         );
 
         assert_eq!(
-            tools[7].spec,
+            tools[8].spec,
             ToolSpec::Function(ResponsesApiTool {
                 name: "test_server/do_something_cool".to_string(),
                 parameters: JsonSchema::Object {

codex-rs/core/tests/suite/model_tools.rs

@@ -57,7 +57,6 @@ async fn collect_tool_identifiers_for_model(model: &str) -> Vec<String> {
     config.model = model.to_string();
     config.model_family =
         find_family_for_model(model).unwrap_or_else(|| panic!("unknown model family for {model}"));
-    config.features.disable(Feature::PlanTool);
     config.features.disable(Feature::ApplyPatchFreeform);
     config.features.disable(Feature::ViewImageTool);
     config.features.disable(Feature::WebSearchRequest);
@@ -98,7 +97,8 @@ async fn model_selects_expected_tools() {
             "local_shell".to_string(),
             "list_mcp_resources".to_string(),
             "list_mcp_resource_templates".to_string(),
-            "read_mcp_resource".to_string()
+            "read_mcp_resource".to_string(),
+            "update_plan".to_string()
         ],
         "codex-mini-latest should expose the local shell tool",
     );
@@ -110,7 +110,8 @@ async fn model_selects_expected_tools() {
             "shell".to_string(),
             "list_mcp_resources".to_string(),
             "list_mcp_resource_templates".to_string(),
-            "read_mcp_resource".to_string()
+            "read_mcp_resource".to_string(),
+            "update_plan".to_string()
         ],
         "o3 should expose the generic shell tool",
     );
@@ -123,6 +124,7 @@ async fn model_selects_expected_tools() {
             "list_mcp_resources".to_string(),
             "list_mcp_resource_templates".to_string(),
             "read_mcp_resource".to_string(),
+            "update_plan".to_string(),
             "apply_patch".to_string()
         ],
         "gpt-5-codex should expose the apply_patch tool",

codex-rs/core/tests/suite/prompt_caching.rs

@@ -186,7 +186,6 @@ async fn prompt_tools_are_consistent_across_requests() {
     config.cwd = cwd.path().to_path_buf();
     config.model_provider = model_provider;
     config.user_instructions = Some("be consistent and helpful".to_string());
-    config.features.enable(Feature::PlanTool);
 
     let conversation_manager =
         ConversationManager::with_auth(CodexAuth::from_api_key("Test API Key"));

codex-rs/core/tests/suite/tool_harness.rs

@@ -106,9 +106,7 @@ async fn update_plan_tool_emits_plan_update_event() -> anyhow::Result<()> {
 
     let server = start_mock_server().await;
 
-    let mut builder = test_codex().with_config(|config| {
+    let mut builder = test_codex();
-        config.features.enable(Feature::PlanTool);
-    });
     let TestCodex {
         codex,
         cwd,
@@ -193,9 +191,7 @@ async fn update_plan_tool_rejects_malformed_payload() -> anyhow::Result<()> {
 
     let server = start_mock_server().await;
 
-    let mut builder = test_codex().with_config(|config| {
+    let mut builder = test_codex();
-        config.features.enable(Feature::PlanTool);
-    });
     let TestCodex {
         codex,
         cwd,

codex-rs/exec/src/cli.rs

@@ -67,10 +67,6 @@ pub struct Cli {
     #[arg(long = "json", alias = "experimental-json", default_value_t = false)]
     pub json: bool,
 
-    /// Whether to include the plan tool in the conversation.
-    #[arg(long = "include-plan-tool")]
-    pub include_plan_tool: Option<bool>,
-
     /// Specifies file where the last message from the agent should be written.
     #[arg(long = "output-last-message", short = 'o', value_name = "FILE")]
     pub last_message_file: Option<PathBuf>,

codex-rs/exec/src/lib.rs

@@ -70,14 +70,9 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
         sandbox_mode: sandbox_mode_cli_arg,
         prompt,
         output_schema: output_schema_path,
-        include_plan_tool,
         config_overrides,
     } = cli;
 
-    if include_plan_tool.is_some() {
-        eprintln!("include-plan-tool is deprecated. Plan tool is now enabled by default.");
-    }
-
     // Determine the prompt source (parent or subcommand) and read from stdin if needed.
     let prompt_arg = match &command {
         // Allow prompt before the subcommand by falling back to the parent-level prompt
@@ -181,7 +176,6 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
         model_provider,
         codex_linux_sandbox_exe,
         base_instructions: None,
-        include_plan_tool: Some(include_plan_tool.unwrap_or(true)),
         include_apply_patch_tool: None,
         include_view_image_tool: None,
         show_raw_agent_reasoning: oss.then_some(true),

codex-rs/mcp-server/src/codex_tool_config.rs

@@ -49,10 +49,6 @@ pub struct CodexToolCallParam {
     /// The set of instructions to use instead of the default ones.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub base_instructions: Option<String>,
-
-    /// Whether to include the plan tool in the conversation.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub include_plan_tool: Option<bool>,
 }
 
 /// Custom enum mirroring [`AskForApproval`], but has an extra dependency on
@@ -145,7 +141,6 @@ impl CodexToolCallParam {
             sandbox,
             config: cli_overrides,
             base_instructions,
-            include_plan_tool,
         } = self;
 
         // Build the `ConfigOverrides` recognized by codex-core.
@@ -159,7 +154,6 @@ impl CodexToolCallParam {
             model_provider: None,
             codex_linux_sandbox_exe,
             base_instructions,
-            include_plan_tool,
             include_apply_patch_tool: None,
             include_view_image_tool: None,
             show_raw_agent_reasoning: None,
@@ -277,10 +271,6 @@ mod tests {
                 "description": "Working directory for the session. If relative, it is resolved against the server process's current working directory.",
                 "type": "string"
               },
-              "include-plan-tool": {
-                "description": "Whether to include the plan tool in the conversation.",
-                "type": "boolean"
-              },
               "model": {
                 "description": "Optional override for the model name (e.g. \"o3\", \"o4-mini\").",
                 "type": "string"

codex-rs/tui/src/lib.rs

@@ -144,7 +144,6 @@ pub async fn run_main(
         config_profile: cli.config_profile.clone(),
         codex_linux_sandbox_exe,
         base_instructions: None,
-        include_plan_tool: Some(true),
         include_apply_patch_tool: None,
         include_view_image_tool: None,
         show_raw_agent_reasoning: cli.oss.then_some(true),

scripts/debug-codex.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Set "chatgpt.cliExecutable": "/Users/<USERNAME>/code/codex/scripts/debug-codex.sh" in VSCode settings to always get the 
+# latest codex-rs binary when debugging Codex Extension.
+
+
+set -euo pipefail
+
+CODEX_RS_DIR=$(realpath "$(dirname "$0")/../codex-rs")
+(cd "$CODEX_RS_DIR" && cargo run --quiet --bin codex -- "$@")